The present invention relates to an arrangement for the drive of a motor vehicle, with a permanently operating four-wheel drive lock-up mechanism arranged in the drive connection front axle-rear axle, with a free-wheeling device and with an engageable by-pass clutch for the free-wheeling device.
Such a drive arrangement is described in the DE-OS No. 33 17 247. The wheels of the front axle are driven permanently and directly by an engine transmission block arranged at the front axle. The drive to the rear axle takes place by means of a viscous coupling disposed in the longitudinal drive connection between the front axle and the rear axle which automatically transmits a driving torque corresponding to the rotational speed difference between the front axle and the rear axle. In order to attain a torque decoupling with a braked vehicle and to improve the driving stability, a free-wheeling device is additionally inserted into the drive connection. When driving the motor vehicle in the reverse or backward direction, a four-wheel drive is also achieved in that a by-pass or bridging clutch is disposed in parallel to the free-wheeling device which is engaged when driving backwards and thus cancels the decoupling from the front axle to the rear axle.
It is the object of the present invention to make such a drive arrangement utilizable by a special constructive design of the drive arrangement essentially without change, for motor vehicles of the most varied type of construction without having to undertake any significant structural changes in these motor vehicles.
The underlying problems are solved according to the present invention in that the four-wheel-locking mechanism and the free-wheeling device together with the by-pass clutch are arranged adjacent one another and coaxially to one another inside of a housing surrounding the same which is adapted to be flangedly connected to an axle housing of the motor vehicle. If the lock-up mechanism together with the free-wheeling device and the by-pass clutch are surrounded coaxially to one another by a cylindrical housing, a compact four-wheel drive unit can be realized which can be installed into the front axle, the rear axle or the longitudinal drive connection of different vehicle types. Preferred as four-wheel-lock-up mechanism is a planetary gear with a brake acting on the planet carrier as described in the DE-PS No. 35 07 490.